A high dynamic range (HDR) sensor captures images across two or more exposure levels from the same scene during the same frame time (simultaneously). The two or more exposures are combined to form a single image with superior quality at both low and high light levels. The HDR sensor may combine the two or more images internally or store out each exposure separately to a digital signal processor (DSP) chip, which then blends the images. The latter approach gives users full control over the blending process.
An alignment problem may arise when the HDR sensor stores each exposure out to the DSP chip. Each exposure level is captured at the same time, but stored through a single interface port to the DSP chip. The HDR sensor typically stores out lines in an interleaved format. In a typical 2 exposure system, the HDR sensor stores one row of a long exposure image followed by one row of a shorter exposure image, followed by a row of the long exposure image, and so on. However, the image capture for each exposure level may not occur at the same time, so the sensor may store out different rows from the long and short exposures at any point and time. Another problem is that the exposures being stored out may also be from different frames within a limited range.
It would be desirable to implement a high dynamic range sensor system with row increment operation.